Oil pressure and spring controlled



Aug. 24,, m7.

-H. VI. HOFIUS OIL P REsSU iE AND SPRING CONTROLLED BUFFER FORTHE'SILENT CLOSING OF DOORS Filed May 17. 1935 JW/ I MMMM;

Patented Aug. 24, 1937 UNITED STATES PATENT OFFICE OIL PRESSURE ANDSPRING CONTROLLED BUFFER FOR THE SILENT CLOSING OF DOORS Application May17, 1935, Serial No. 22,011 In Germany May 12, 1934 a 1 Claim.

This invention relates to an oil pressure and spring controlled bufierfor the silent closing of doors.

Hydraulic brakes and buffer rams subjected to 5 spring action arealready known. These constructions are so-called shock absorbers fordoors which cooperate with cylinders mounted on the door wings. Suchcylinders are unsightly and, owing to the complicated construction, theyare uneconomical. The pressure in these devices acts in difierentstrengths, also on the shock absorbers, so that by exerting considerableforce it is possible to quickly close the door.

The invention overcomes these objections and has for its object toreliably prevent the slamming and banging of doors by very simple means.

It must therefore be impossible on the one hand to bang a door byexerting considerable force and it must be possible on the other hand toclose the door by exerting slight pressure. This problem is solvedaccording to the invention which utilizes the inertia of the masseswhich offers considerable resistance under heavy pressure and easilyyields under light slowly-applied pressure.

The device according to the invention is characterized in that a bufferram carrying on its outer end a rubber pad is acted upon by a spiralspring and guided in a cylinder having a conically tapered end with anair outlet aperture and ac- 30 commodated in an oil container having anair port.

This device enables a perfectly silent closing of the door.

An embodiment of the invention is illustrated 3:, by way of example inthe accompanying drawing,

in which:--

Fig. 1 is a perspective view of the edge of a door frame with a buffermounted therein.

Fig. 2 is a longitudinal section through the 40 buffer on a largerscale.

A bufier ram b with rubber pad 0 is mounted in a lock-like casing in adoor frame a. Buffers of this kind are preferably arranged between thedoor lock and the upper and lower ends of the door respectively. Thebufier ram b is tightly guided in an oil cylinder d and continuallypressed outwardly by a spiral spring e bearing against its inner end.This spiral spring is likewise mounted in the oil cylinder d, the innerend 1 of which conically tapers to a point with an aperture y.

As soon as the rubber pad 0 is subjected to pressure by the slamming ofthe door, its ram 12 forces the oil out of the cylinder d through theadjustable aperture 9 into an oil collecting container 71 provided withan air port 1; for the escapement of air.

The door movement is retarded by the new buffer so that no noise isproduced by the slamming or gentle closing of the door.

I claim:-

An oil pressure and spring controlled bufier for the silent closing ofdoors, comprising in combination a casing let into the door frame, anoil container at the inner end of said casing having an air escapementport near its upper end, an oil cylinder in said casing extending fromthe front wall thereof to the lower end of said oil container, a conicalextension on the inner end of said cylinder projecting into said oilcontainer and having at its point a small aperture establishingpermanent communication between said container and said cylinder for thefree passage of oil between said cylinder and said container, a solidram slidable in said cylinder and normally projecting from the outer endthereof, said ram adapted to force the oil out of said cylinder throughsaid aperture into said container when pressure is exerted on itsprojecting outer end, a spiral spring in said cylinder and said conicalextension bearing against the inner end of said ram and adapted toreturn said ram into its initial position and allow the oil to flow fromsaid container through the aperture in said extension to form an oilcushion in said cylinder, and a rubber pad on the projecting outer endof said ram adapted to absorb shocks exerted on said piston.

HEINRICH WILHELM HOFIUS.

